1. Field of the Invention
The present invention relates to an apparatus for producing optical elements such as lenses, prisms, mirrors, filters or the like, and more particularly to such apparatus suitable for continuous production of optical elements having vacuum evaporated layers on the functional faces of such elements.
2. Related Background Art
Optical elements, such as lens, prism, mirror or filter, are generally produced by grinding a material such as glass to a desired shape, then polishing functional faces thereof which transmit and/or reflect light to an optically smooth state, sufficiently washing said faces and depositing an anti-reflection layer or a reflection enhancing layer onto such functional faces for example by vacuum evaporation method.
However, such production has required considerable labor of experienced workers in order to obtain a desired surface precision, i.e., desired surface form and coarseness, by means of grinding and polishing. Also for depositing the thin layer onto the functional faces after polishing, a considerable time has to be spent in meticulous washing for removing the polishing material deposited in the polishing step. Furthermore, in thin layer deposition, for example by vacuum evaporation, which is usually conducted in a batch process wherein a plurality of materials for optical elements are simultaneously processed in a vacuum apparatus, it is desirable to place all the materials at the same distance from the source of evaporation. For this reason, there is required an operation of placing the materials for the optical elements on an umbrellashaped support member provided with plural apertured support seats, and said operation cannot be easily automated and cannot be considered efficient in mass production.
As explained in the foregoing, the conventional process for producing optical elements consists of independent process steps which are conducted in separate apparatus, so that there are required ancillary works such as the transportation of the material by the workers between different process steps and the setting of the materials on the process apparatus. Also, the formation of the functional faces by grinding and polishing increases the number of process steps and necessitates a meticulous washing step prior to the deposition of thin layer, and a significant storage space is indispensable for the products in process, due to the difference in the speeds of the process steps. For these reasons the production efficiency is not satisfactorily high.